Process of recovering borax from saline waters



UNITED ElTrtTE GEORGE E. BUEMHAM. OF BQIBZGESUIEIVAE',

PROCESS or nnoovnmne nos FRUH'. SALINE W i113? No Drawing. Application filed June 50,

To all whom 2'25 may concern Be it known that I, Gnonsn Bonnrrnza, a citizen of the United States, and a resident of Borosolvay, San Bernardino county, State of California, have invented a. certain new and useful Process of Recovering Borax from Saline Waters, of which the following is a specification.

The invention relates to a process of recovering sodium tetraborate from saline waters containing the same, and partifcularly from the brines of the lkali lakes of the western United States.

An object of the invention is to provide a cheap process for recovering borax from saline waters containing the same.

The invention possesses other advantageous features. some of which, with the foregoing, will be set forth at lenr the following description, where l sha line in full. one form of the process o h invention. 1 shall describe the process as applied to the brine of Searles Lake in (latifornia, but it is to be understood that a process is not limited to this particular brine.

Searles Lake brine contains sodium. potas sium. chlorid, sulfate, carbonate. bicarbonate and borate ions. By the process of my vention, I am able to employ natural temperatures for evaporation and cooling, and I prefer to make use of the temperature yariations of winter and summer and day and night. but artificial variations in temperature may be employed when desired. flow-- ever, when carbonates are present. in Searles Lake brine, the natural temperatures which are employed tor-evaporation have a greater advantage in the recovery of the more insoluble borax salts. than high artificial temperatures, since at high temperatures a reaction between the carbonates and borates may ocrur. which may produce decomposition of the sodium tct-rabora e.

In the preferred form of my process, the lake brine is pumped in the early summer into large solar evaporation ponds. wherein. a portion of the water content is evaporated. increasing the concentration of the borax to as high a degree as is possible. As concentration increases, due to evaporation. sodium chlorid is crystallized out. Further evaporation may be carried on in these ponds or the remaining brine may he transferred to other solar e' eporation ponds, before other materials begin to Specification of Letters Patent.

Evaporation is then wntinucd, iuin rhlorid, potassium sodium sulfate and sodiiun carbonate sulfate to This stage of the evaporaren'iores sodium, potassium, chlorid, ate and carbonate'ions from the brine u increases the concentration of the borax.

first ponds (in the erent that the brine is not transferred) is continued until sodium carbonate sulfate ceases to crystallize out and until the (trona) beqins to crystallize out and is further continued until the brine becomes sat-uth borax. This condition is reached The amount of evaporawach saturation with boraX "1:: year can be governed e brine in the ponds durin the summer. then preferably flowed or ds. in which the brine and winter, causing l 'ater may be .allize out.

1: no in the cooling ponds to 'a 'ioration which takes p ace t wr i thus prevent crystallization oi other salts with the wax in these )onds. due to evaporation. ll s been suiliciently chillml ystailization hora antler the existingtil'ilpilii illli-R. the rema ning brine owed from the cooling; ponds and the crude borax crystals collected. The chi f impurities lize out with the hora): upon-cooling are carbonate s: and v..rious methods of refining can be en'ipioved, forth belo In tead of removing: the brine from the .or second ponds, ru'ior to cooling. t brine may remain in the cooling, the borax crystals will bodeposited on top of the previously deposited crystals. and subseruieu j the lunar: rrystals separated from the others. The borax crystals are line-g?!" i red and loose, and are easily reznrred w I ran the brine cause the which crystali i a hydraulic dredge. fioat on the pond. The previously dep s l crystals lilllll somewhat fire deposit in. the

invaporation in these second ponds or in the I sesqui carbonate of soda same pond and on mechanical and chemical methods. For instance, the recovered crystals may be Washed with water, causing the more readily soluble salts to be dissolved, leaving the borax crystals behind.

Several methods of mechanical separation have been employed with success. In one method, the crystals drawn up by the dredge were discharged into a long, narrow pond, in which the coarser salts settled quickly adjacent the end of the discharge pipe and the fine-grained borax crystals floated away and settled in the pond at points remote from the discharge pipe.

In another method, the pumped mixture of brine and crystals was flowed through a trough .having a perforated bottom, submerged in a brine-vat or pond. The coarse salts passed through the holes in the bottom of the trough and the fine borax crystals were carried along in the brine stream and,

discharged from the end of the trough into a settling pond. Other mechanical methods of separation using the diilerence in size of the various crystals have also been employed to advantage.

Besides the recovery of borax, it may be desirable to effect a. separation and reco ery ot the other salts in the brine that cry; tal

lize outduring the evaporation and cooling stages; In some cases these various salts are deposited in loose and separate crystals and are then very easily subjected to mechanical separation. In other cases the individual crystals are slightly stuck to gether and in such case are gathered and gently crushed, thereby separating the crystale. The various diil'er-ent salts can then be mechanically separated from each other by making use of the d'ifi'erence in sizes and shapes of the crystals and their dill'erent specific gravities. In this way most of the valuable s'alts can be recovered from the brine.

I claim 1. The process of recovering borax from natural liquors containing sodium, potassium, chlorid, sulfate, carbonate and bot-ate ions comprising evaporating the liquor to crystallize out sodium, potassium, chlorid, sulfate and carbonate salts and increase the neroma concentration of the borate ions and then cooling the resultant liquor to crystallize out borax.

2. The process of recovering borax from natural liquors containing sodium, potassium, chlorid, sulfate, carbonate and borate ions comprising evaporating the liquor to crystallize out sodium, potassium, chlorid, sulfate and carbonate salts and increase the concentration of the borate ions, separating the resultant liquor from the deposited crystals and then cooling the resultant liquor to crystallize out borer and carbonate salts and separating the borax from the deposited salts.

3. The. process of recovering borax from liquors containing sodium, potassium, chlorid, sulfates, carbonate and borate ions comprising evaporating the liquor to crystallize out sodium, potassium, chlorid, sulfate and carbonate salts and increase the concentration of the horate'ions. separating the resultant liquor from the deposited crystals, adding water to the resultant liquor and then cooling the liquor to crystallize out borax. 4

4-. The process of recovering be at from natural liquors containing sodium, potassium, chlorid, sulfate, carbonate and borate ions, which consists in exposing the liquor to solar evaporation whereby it is kept rela tively Warm and potassium, sodium, chlorid, sulfate, and carbonate salts are crystallized out and then chilling the liquor to crystallize out'borax and separating the borax from the liquor.

5. The process of recovering borax from liquors containing borax, sodium carbonate and other salts, which consists in evaporating the liquor to crystallize out a portion of the other sails, removing the liquor from the deposited crystals, cooling the removed liquor to crystallize out hora); and carbonate salts and separating the hora); from the carbonate. .7

In testimony whereof, I have hereunto set my hand at San Francisco, California, this 9th day of June 1919.

GEORGE ll. BURNllAlll lnpresence of H. G. Prom. 

